How can this floor be renewed?

You can paint it or lay down vinyl plank flooring over it. Looks like wood, ceramic or porcelain tile.

Painting ideas from other Hometalkers.

https://www.hometalk.com/search/posts?filter=paint%20vinyl%20floors

U can paint it and stencils it, I am going to use chalk paint then a large stencil.then a glaze

I don't think it's a stain, but discoloration from years of sunlight and use. I don't think it can be removed.

Agree with Fiddledd that the discolouration in the vinyl is just due to age, 30 years exposure to incandescent light, and all the various substances normally found on a bathroom floor.

Unfortunately, it is permanent, but after this number of years, I would say that the flooring has exceeded its 'shelf life'. It can not be rejuvenated back to new with any other way other than simply replacing it with a more modern flooring.

You can use porch paint and paint over it! Here's an image of a bathroom where this person did just that this week: https://www.instagram.com/p/BoIVoYZg1iO/?hl=en&taken-by=cynthia_harper_

I would float a water resistant vinyl plank floor right over this. You can be done in a day! You could also use stick on vinyl tiles--but if you choose this you have to use a adhesive primer first. Vinyl stick on tiles would be less money than a floating floor but this looks like a small bathroom so even then it is affordable. Take up your toilet before you put flooring down--buy a new wax ring or two to reseat the toilet.